that the singer's longtime beau and "Criminal" co-star Jason Trawick planned to pop the question Friday night (December 16) in Las Vegas, the singer took to Twitter early Friday and had this mysterious message for her fans.

"OMG. Last night Jason surprised me with the one gift I've been waiting for," she

A rep for the singer hadn't responded to MTV News' request for comment by press time, but sources confirmed the news to People magazine. TMZ further reports that Jason asked Britney's dad, Jamie, for his daughter's hand before he popped the question. According to reports, Britney already knew about the engagement and the couple will sign a prenuptial agreement.

As for her conservatorship, her conservators have signed off on the couple's plans to marry; a judge will most likely give them the go-ahead to tie the knot.

A source tells Usmagazine.com that Trawick asked his lady love to marry him on Thursday night while the two were at a romantic dinner celebrating his 40th birthday. The couple will celebrate the engagement at Planet Hollywood in Las Vegas on Friday. "This is something they've both wanted for a long time," the source told the site. "It's a way to cement their family. They're both extremely happy and can't wait to become man and wife."

The Neil Lane ring is a four-carat, round-cut diamond with micro pave diamonds around the band, according to E! News. "It's classic, simple and beautiful," a rep for the jewelry company told the site. The rep added that Trawick worked with the designer to design a "dream ring" for his future wife.

While there's no confirmation from Spears' camp just yet about the engagement, Spears did reveal something on Twitter: what she bought Jason for his birthday.

"Hbday Jason! He looked so cool in the video, that I had to get him a new motorcycle," she wrote. "Check out this new Confederate Bike I got him!"